1. Field of the Invention
This invention relates to novel poly(ethynylphenyl)acetylene, its copolymers and compositions thereof which are useful as electron-beam resist, photosensitive resin, and heat-resistant resins.
2. Description of the Prior Art
Branching polyphenylene compounds which contain an ethynyl group linked with an aromatic ring are disclosed in U.S. Pat. Nos. 3,882,073 and 4,070,333. However, due to the use of a catalyst which can cause cyclotrimerization of the ethynyl group in the polymerization, the main chain of the polymer cannot be constructed by a conjugated double bond. Further, these polymers have a drawback that the use is limited.
lt has been described in Macromolecules, Vol. 7, p. 728 (1974) and ibid, Vol. 8, p. 717 (1975) that tungsten hexachloride and molybdenum pentachloride can be employed as a catalyst for polymerization of a substituted acetylene. Further, it has been described in Macromolecules, Vol. 9, p. 661 (1976) that both tungsten hexachloride and molybdenum pentachloride show higher activities when they are employed with a little water or reducing agents such as tetraphenyltin. In Polym. Bull., Vo. 2, p. 828 (1980) and Polymer, Vol. 23, p. 1663 (1982), it has been described that active catalyst for polymerization of a substituted acetylene can be obtained by irradiating light from a high-pressure mercury lamp to tungsten hexacarbonyl or molybdenum hexacarbonyl in the presence of a halogenated hydrocarbon. It has been suggested by the authors of the above-described publications that these catalysts may make a metal carbene complex in the beginning of the reaction by reacting with a monomer, that is, a substituted acetylene, under reduction condition, and the metal carbene complex may act as a catalyst for polymerizing the substituted acetylene.
However, these catalysts have never been used for polymerizing an aromatic disubstituted acetylene such as diethynylbenzene. In fact, these catalysts are not useful to obtain the polymers of this invention because when these catalysts are employed, a micro gel having a three-dimensional cross-linked structure is produced, and linear polymers are hardly obtained.
Ziegler-Natta catalysts which are well known polymerization catalysts of acetylene are also not useful for polymerizing the aromatic disubstituted acetylene for the same reasons as described above. lt is recognized that cross linking reaction occurs together with the polymerization of the substituted acetylene when these known catalysts are employed. Actually, nobody have reported that Ziegler-Natta catalysts can be employed for polymerizing the aromatic disubstituted acetylene.